White-tailed Tyrannulet

The white-tailed tyrannulet is about 11 cm (4.3 in) long and weighs 10 to 11 g (0.35 to 0.39 oz). The sexes have the same plumage. Adults have a medium gray crown. They have a thin white supercilium and a faint blackish stripe through the eye on an otherwise whitish face. Their upperparts are mostly greenish olive with a bright greenish yellow rump and uppertail coverts. Their wings are dusky with pale yellow edges on the flight feathers. Their wing coverts have white to pale buff tips that show as two bars on the closed wing. Voice: The white-tailed tyrannulet's dawn song is "a high, lisping pseeee-psweet". Its day song is "a descending series of high, rising, sibilant whistles: PSEE pswee pswee psweet" that sometimes ends with "sharper pit notes".